Image-guided treatment of cancer enables physicians to localize and treat tumors with great precision. Here, we present in vivo results showing that an emerging imaging modality, magnetic particle ...imaging (MPI), can be combined with magnetic hyperthermia into an image-guided theranostic platform. MPI is a noninvasive 3D tomographic imaging method with high sensitivity and contrast, zero ionizing radiation, and is linearly quantitative at any depth with no view limitations. The same superparamagnetic iron oxide nanoparticle (SPIONs) tracers imaged in MPI can also be excited to generate heat for magnetic hyperthermia. In this study, we demonstrate a theranostic platform, with quantitative MPI image guidance for treatment planning and use of the MPI gradients for spatial localization of magnetic hyperthermia to arbitrarily selected regions. This addresses a key challenge of conventional magnetic hyperthermiaSPIONs delivered systemically accumulate in off-target organs (e.g., liver and spleen), and difficulty in localizing hyperthermia results in collateral heat damage to these organs. Using a MPI magnetic hyperthermia workflow, we demonstrate image-guided spatial localization of hyperthermia to the tumor while minimizing collateral damage to the nearby liver (1–2 cm distance). Localization of thermal damage and therapy was validated with luciferase activity and histological assessment. Apart from localizing thermal therapy, the technique presented here can also be extended to localize actuation of drug release and other biomechanical-based therapies. With high contrast and high sensitivity imaging combined with precise control and localization of the actuated therapy, MPI is a powerful platform for magnetic-based theranostics.
A review is provided, which first considers low-temperature diffusion bonding with silver nanomaterials as filler materials via thermal sintering for microelectronic applications, and then other ...recent innovations in low-temperature joining are discussed. The theoretical background and transition of applications from micro to nanoparticle (NP) pastes based on joining using silver filler materials and nanojoining mechanisms are elucidated. The mechanical and electrical properties of sintered silver nanomaterial joints at low temperatures are discussed in terms of the key influencing factors, such as porosity and coverage of substrates, parameters for the sintering processes, and the size and shape of nanomaterials. Further, the use of sintered silver nanomaterials for printable electronics and as robust surface-enhanced Raman spectroscopy substrates by exploiting their optical properties is also considered. Other low-temperature nanojoining strategies such as optical welding of silver nanowires (NWs) through a plasmonic heating effect by visible light irradiation, ultrafast laser nanojoining, and ion-activated joining of silver NPs using ionic solvents are also summarized. In addition, pressure-driven joining of silver NWs with large plastic deformation and self-joining of gold or silver NWs via oriented attachment of clean and activated surfaces are summarized. Finally, at the end of this review, the future outlook for joining applications with silver nanomaterials is explored.
Osteoarthritis is a common disease that can cause severe pain and dysfunction in any joint, including the temporomandibular joint (TMJ). TMJ osteoarthritis (TMJOA) is an important subtype in the ...classification of temporomandibular disorders. TMJOA pathology is characterized by progressive cartilage degradation, subchondral bone remodeling, and chronic inflammation in the synovial tissue. However, the exact pathogenesis and process of TMJOA remain to be understood. An increasing number of studies have recently focused on inflammation and remodeling of subchondral bone during the early stage of TMJOA, which may elucidate the possible mechanism of initiation and progression of TMJOA. The treatment strategy for TMJOA aims at relieving pain, preventing the progression of cartilage and subchondral bone destruction, and restoring joint function. Conservative therapy with nonsteroidal anti-inflammatory drugs, splint, and physical therapy, such as low-energy laser and arthrocentesis, are the most common treatments for TMJOA. These therapies are effective in most cases in relieving the signs and symptoms, but their long-term therapeutic effect on the pathologic articular structure is unsatisfactory. A treatment that can reverse the damage of TMJOA remains unavailable to date. Treatments that prevent the progression of cartilage degradation and subchondral bone damage should be explored, and regeneration for the TMJ may provide the ideal long-term solution. This review summarizes the current understanding of mechanisms underlying the pathogenesis and treatment of TMJOA.
The brittleness of dissimilar NiTi-stainless steel (SS) welds caused by intermetallic compounds (IMCs) network limits their application in medical field. Inserting interlayer and special assembly are ...high-cost but still hard to eradicate the formation of IMCs. This work realized NiTi-SS wire joints with a high strength using laser welding-brazing mode through beam defocus and large offset. The effect of laser beam offset on joint appearance, microstructure, tensile strength and fractography was investigated. In welded-brazed joints, a fusion zone (FZ) of only one base metal formed while multilayered reaction microstructure at the brazed interface was observed. Without beam offset, a typical FZ was dominated by Ni3Ti+Fe2Ti IMCs network. The tensile strength was improved from 176.6 MPa of conventional welding mode without offset to 329.5 MPa of welding-brazing mode with 0.4-mm offset to SS side. The joint welded with large offset fractured at the brazed interface with a mixed ductile-brittle fracture; while brittle fracture inside the IMCs network of FZ was observed in the joint welded without beam offset. The enhancement of joint strength was attributed to the eradication of IMCs network in the FZ and a reaction layer with less Ti–Fe brittle IMCs. This welding-brazing mode can be applied to suppress the overall brittleness of NiTi-SS joints without using any interlayer.
•Join NiTi and 304 stainless steel wires using a laser welding-brazing mode for the first time.•Uncover microstructural evolution and mechanical properties of welded-brazed NiTi-steel joints.•Overcome the overall brittleness of NiTi-steel joints by eradicating IMCs network in the fusion zone.•Propose a solution for no-interlayer joining of dissimilar materials with similar melting point.
•Moving crack in 1D hexagonal piezoelectric quasicrystals is studied.•Full electroelastic field induced by a running crack is obtained.•Field intensity factor is independent of the crack ...speed.•Energy release rate is dependent on the crack speed.•Crack bifurcation is judged by the maximum energy release rate.
A Yoffe-type moving crack in one-dimensional hexagonal piezoelectric quasicrystals is considered. The Fourier transform technique is used to solve a moving crack problem under the action of antiplane shear and inplane electric field. Full elastic stresses of phonon and phason fields and electric fields are derived for a crack running with constant speed in the periodic plane. Obtained results show that the coupled elastic fields inside piezoelectric quasicrystals depend on the speed of crack propagation, and exhibit the usual square-root singularity at the moving crack tip. Electric field and phason stresses do not have singularity and electric displacement and phonon stresses have the inverse square-root singularity at the crack tip for a permeable crack. The field intensity factors and energy release rates are obtained in closed form. The crack velocity does not affect the field intensity factors, but alters the dynamic energy release rate. Bifurcation angle of a moving crack in a 1D hexagonal piezoelectric quasicrystal is evaluated from the viewpoint of energy balance. Obtained results are helpful to better understanding crack advance in piezoelectric quasicrystals.
This study examines the patterns and predictors of post-traumatic stress disorder (PTSD) symptom trajectories among adolescent survivors following the Wenchuan earthquake in China.
A total of 1573 ...adolescent survivors were followed up at 6, 12, 18 and 24 months post-earthquake. Participants completed the Posttraumatic Stress Disorder Self-Rating Scale (PTSD-SS), Adolescent Self-Rating Life Events Checklist, Social Support Rate Scale, and the Simplified Coping Style Questionnaire. Distinct patterns of PTSD symptom trajectories were established through grouping participants based on time-varying changes of developing PTSD (i.e. reaching the clinical cut-off on the PTSD-SS). Multivariate logistic regressions were used to examine predictors for trajectory membership.
PTSD prevalence rates at 6, 12, 18 and 24 months were 21.0, 23.3, 13.5 and 14.7%, respectively. Five PTSD symptom trajectories were observed: resistance (65.3% of the sample), recovery (20.0%), relapsing/remitting (3.3%), delayed dysfunction (4.2%) and chronic dysfunction (7.2%). Female gender and senior grade were related to higher risk of developing PTSD symptoms in at least one time point, whereas being an only child increased the possibility of recovery relative to chronic dysfunction. Family members' injury/loss and witness of traumatic scenes could also cause PTSD chronicity. More negative life events, less social support, more negative coping and less positive coping were also common predictors for not developing resistance or recovery.
Adolescents' PTSD symptoms showed an anniversary reaction. Although many adolescents remain euthymic or recover over time, some adolescents, especially those with the risk factors noted above, exhibit chronic, delayed or relapsing symptoms. Thus, the need for individualized intervention with these adolescents is indicated.
Esketamine, one of the few non-opioid potent analgesics, has demonstrated efficacy in the treatment of various chronic pain, particularly neuropathic pain. However, its potential clinical ...applications are confined due to its short half-life and severe side effects including delirium, hallucinations, and other psychiatric symptoms. Here, we reported a nanosized drug delivery system for sustained-release esketamine based on polylactic-co-glycolic acid (PLGA) nanoparticles and hyaluronic acid (HA) hydrogel.
In this study, esketamine in the delivery system was continuously released in vitro for at least 21 days, and spinal nerve root administration of the delivery system successfully attenuated (spinal nerve ligation) SNL-induced pain hypersensitivity for at least 14 days. Notably, the excitability of neurons in murine dorsal root ganglion (DRG) was inhibited and the activation of astrocytes in the spinal cord was additionally reduced after administration. Finally, there was no obvious pathophysiological change in the nerves at the administration site after treatment at 14 days.
These results indicate that the sustained-release esketamine based on the nanoparticle-hydrogel delivery system can safely produce a lasting analgesic effect on SNL mice, and its mechanism might be related to modulating the activation of astrocytes in the spinal cord and inhibiting the excitability of neurons in DRG.
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